Lathe and shaper tool bit grinding gauge



Dec. 26, 1944. H, HQWE v LATHE AND SHAPER TooLBIT GRINDING GAUGE Filed Dec. 25, 1942 Patented Dec. 26, 1944 LATHE AND SHAPER TOOL BIT GRINDING GAUGE Louis H. Howe, Portland, Oreg.

Application December 23, 1942, Serial No. 469,923

(Cl. 51-221l 4 Claims.

" This invention relates generally to machine tools and particularly to the grinding of toolbits.

The main objectof this invention is to simplify the sharpening of lathe, shaper and planer toolbits.

The second object is to so sharpen a bit as to make it hold its cutting edge as long as possible,

to improve the quality and increase the quantity.

of the work performed thereby and to reduce the amount of time ordinarily spent in sharpening bits as well as to reduce the Waste of steel caused by incorrect sharpening.

The third object is to provide an improved clamping action for holding bits of various sizes.

I accomplish these and other objects` in the manner set forth in the following specification as illustrated in the accompanying drawing, in

which: y

Fig. 1 is a fragmentary plan of a double wheel grinder showing the relation of the gauge and the grinding Iwheels while grinding the clearance angles on a bit.

Figure 2 is an end elevation of the gauge taken along the line 2-2 in Fig.' 3.

Figure 3 is a vertical section taken along the line 3-3 in Fig. 2. y

Figure 4 is a side elevation of the gauge.

Figure 5 is a transverse section taken along the line 5-5 in Fig. 3.'

Figure 6 is a transverse section takenalong the line 6-6 in Fig'. 3..

Similar numerals refer to similar parts throughout the several views.

Referring in detail to the drawing; there is shown a common form of wheel grinder having two abrasive wheels I and`-|| mounted on a spindle I2 and driven by a belt I3 which passes around the pulley |4. The table is provided as a rest upon which the gauge is placed.

Referring to my invention, same consists of a base I6 having the parallel sides` I1 which are joined by the end I8. Across the sides is mounted the screw I9 on which is hinged the square arm having the bore 2| extending therethrough. A spring 22 disposed between the end of the arm 20 and the end I1 tends to urge the free end of the arm 20 downwardly.

Resting upon the base I6 is a shoe 23 into which is threaded an adjusting screw 24 which is provided with a kn'urled head 25 at the end thereof which is remote from the shoe 23, which screw end journals in the end Il. The shoe 23 has its uppermost edge 26 contacting the under side 29 of the arm 20. The purpose of this construction is to make it possible to adjust the vertical angle of the arm 20 by turning the head 25.

The arm 2|) has formed on the end remote from the screw I9 a somewhat circular ange Y 21 whose under edge 28 is flattened to conform to the under side 29 of the arm 20.

Within the bore 2| is a, split bit holding sleeve whose lower portion 30 is integral with the circular f lange 3|. The end 32 of the sleeve por-` tion 30 projects beyond the flange 3|. The upper sleeve portion 32 also extends into the bore 2| and with the part 30 is free to turn and slide therein. The end 33 extends beyond the fiange 3| as does the end of the sleeve part 3|).

The portion 33 has threaded therethrough a clamping screw 34 which is provided with a knurled head 35.

There is also shown a `representative form of bit having a square shank 36 showing the front clearance face 31, the side clearance face 3B and the slope 39. f

The edge 40 of the flange 21 is calibrated in degrees and the edge 4| of the fiange 3| is provided with mark 42 which can be brought into register with the degree marks on the edge 40, thereby making it easily possible to set the sleeve parts 30 and 32 and the bit shank 36 which is placed therein at any desired angle in a plane normal to the axis of the bore 2|, thereby establishing the side clearance.

The front clearance is determined by the calibrated arc 43 on the arm 20 and thetcoinciding mark 44 on the side Il. The adjustment is made by rotating the screw 24 which varies the angle of the arm 20.

Since the slope 39 is on aside of the shank 38 which is normal to the shank portions on which the side and end clearances are formed, it follows that if the calibrations on the flange 21 used for grinding the side clearance are to be used for grinding the slope, then the bit shank 36 must be turned 90 degrees yin its holder.

It will be noted that when the screw 34 is tightened, the bit shank 36 is forced against the lower sleeve portion 30, while the upper sleeve portion 32 is forced in the opposite direction thereby clamping the bit 36 and the parts 30 and 32 to the arm 2D. As illustrated in Fig. 1, the front clearance is ground on wheel I0 and the side clearance is ground on wheel The slope is ground on wheel vII). Obviously the conditions are reversed for right and left hand bits.

It can be seen that with this gauge, a blt can beproperly ground by an inexperienced person, using the least time and material and at the same time producing the correct clearance and slope angles thereby making the tool last longer and turning out more and better work while in use.

I claim:

V1. A gauge of the class described including a base adapted to slide in any direction on a flat tool rest, an arm hinged on said base, means for adjusting the angular relationship of said arm and base, a split sleeve rotatably mounted in said arm having a square opening between the portions thereof adapted to receive a bit, said sleeve portions extending lfrom said arm and a ciamping screw threaded through one of the extending sleeve portions adapted to engage a bit held therein and force the sleeve portions into engagement with said arm for the purpose of clamping the bit'with relation thereto.

2. A gauge consisting of a channel shaped base having an arm hinged therein, a shoe mounted for sliding movement o n said base under said arm adapted to limit its downward movement a degree scale and marker between said arm and base, a split sleeve rotatably mounted in said arm, the sleeve portions having square grooves formed in adjacent faces, together forming a square opening for a bit and a screw threaded through one sleeve portion and engaging said bit.

3. A tool holder and grinding gauge consisting of a flat base adapted to slide in any horizontal direction on a ilat tool rest, an arm hinged on said base on a horizontal axis, means for clamping said arm in a predetermined position, said arm having a cylindrical bore extending longitudinally therethrough, a long split sleeve rotatably mounted in said bore, one portion of said split sleeve having a clamping screw extending. therethrough normal to its axis adapted to hold a tool bit against one side of the sleeve and to urge the two portions of the sleeve apart into a clamping relationship with 4the bore of said arm.

4. In a device of the class described a combination of a horizontal table constituting a tool rest having a fixed relation to the grinding wheel, a gauge having a iiat base adapted to rest on said table and to be slidably moveable thereon in any direction, an arm hinged on said base on a horizontal axis, means for fixing said arm at a predetermined angle of inclination, said arm having a longitudinal bore formed therethrough', said 

